When you use your arms, gesture from the shoulder--not your elbow--to avoid looking like you are doing the chicken dance.
You should be neat and organized. Dress for the environment--a suit in a formal business presentation, but more casual if you're at, say, a tech MeetUp. When it comes to presentation slides, title each one and highlight key words, be sure to spell-check and ask a colleague to review your materials. Limit any "cute" or "funny" visuals, especially if you're reviewing a serious subject.
You don't want to distract your audience--or inadvertently convey disdain--with visual effects like rolling your eyes. This is especially true when you're responding to questions, or comments, and you don't want to appear impatient.